The objectives of the proposed research are to investigate the rheological behavior of red blood cell (RBC) membranes, to study the interactions of RBC membranes with the environment, and to correlate these functions with the molecular organization of RBC membranes, both in health and in hematological diseases. The rheology of normal and abnormal RBC membranes during deformation at constant area and during area stretching (including hemolysis) will be experimentally studied, modelled by theoretical computation, and correlated with membrane structure determined by ultrastructural and cytochemical methods. The mechanism of membrane transport of hexoses will be studied in RBC ghosts, and the transport will be correlated with the molecular organization of RBC membranes determined by cytochemical methods. The expression of i-I antigens on the exoface of sickle cell membrane will be correlated with the cell content of HbF. The forces involved in the interaction of the membrane exoface with macromolecules (including abnormal plasma proteins) will be studied experimentally, and the micromechanics of cell aggregation will be modelled theoretically. The ultimate aim of the research is to provide the fundamental knowledge needed for improving the diagnosis and treatment of hematological diseases. BIBBIOGRAPHIC REFERENCES: Chien, S.: Red cell aggregation: studies on colloid-chemical and interfacial phenomena in a biological system. Abstracts of 49th National Colloid Symposium, June 16-18, 1975, Clarkson College, Potsdam, N.Y., p. 83; Usami, S., Chien, S., Scholz, P.M., and Bertles, J.F.: Effect of deoxygenation on blood rheology in sickle cell disease. Microvasc. Res. 9:324-334, 1975.